Drug Resistance

HIV Drug Resistance Basics

When you are first diagnosed with HIV infection, your blood is full of copies of the HIV virus, all looking for CD4 cells that they can attach themselves to. This virus is called “wild type,” because it has never been challenged by the HIV medications that can control it.

Once you start treatment, the goal is to keep HIV from reproducing. When HIV isn't fully controlled by HIV drugs, the virus makes copies of itself at a very rapid rate. Because this replication is occurring so fast, HIV often makes mistakes in the copies. If these “mistaken copies” are able to reproduce themselves, they are called mutations—which creates new forms of the virus.

Mutations may not respond to existing HIV drugs—a characteristic known as resistance. This means that the drugs are less effective and do not stop the virus from multiplying. If your healthcare provider suspects that you have a drug-resistant virus, he or she can do drug resistance testing (called genotyping or phenotyping) to find out if you have drug-resistant HIV and which of your meds may have stopped working.

Reducing Drug Resistance

You can help reduce the chances that you will develop drug-resistant forms of HIV by taking a few simple steps:

Work with your healthcare provider to find a drug combination that is effective and that you can tolerate.

Take every dose of every medication every day, missing as few as possible.

Keep your appointments with your HIV clinician and have your CD4 count and viral load checked every 3-4 months. Those tests will help detect resistance so that, if necessary, you can make changes to your treatment plan and keep your HIV under control.